Structure of the repulsive gel/glass in suspensions of charged colloidal platelets

Abstract

Rheological, optical and structural properties of colloidal suspensions of charge-stabilized gibbsite platelets across the sol–gel transition region are investigated. In this work we focus on samples with a low salt content (10−4 M). While at a gibbsite concentration of 300 g l−1, a nematic–columnar phase separation is observed, an arrested state with a nematic signature and highly elastic response has been observed for a concentration of 400 g l−1. A temporal evolution of the structure of the arrested state, which leads to stronger interparticle correlations, has been observed on a timescale of 20 months. The results suggest that the arrested state develops into a glass with a columnar nematic structure.